Heathrow has launched an investigation after a leak of security information was discovered on a USB stick
Maps, videos and documents related to the airport's security were discovered without passwords or encryption, The Sunday Mirror reports, after a man discovered the USB stick and handed it to the newspaper.
The airport said it was investigating after the newspaper alerted it to the discovery.
In a statement, the airport said it was confident that Heathrow is secure. "We have also launched an internal investigation to understand how this happened and are taking steps to prevent a similar occurrence in future.
"The UK and Heathrow have some of the most robust aviation security measures in the world, and we remain vigilant to evolving threats by updating our procedures on a daily basis."
Information on the USB stick is said to have included the route the Queen takes when going to the airport and the security around her travel and maps of CCTV cameras around the Heathrow Express.